The physics reach of these searches can be further extended by considering decays such as \(\tau ^-\rightarrow \overline{p}\mu ^+\mu ^-\)  and \(\tau ^-\rightarrow p\mu ^-\mu ^-\) ,
which are also baryon number violating and lepton number violating,
whilst still containing multiple final-state muons. These decays both have \(\Delta ( B - L ) = 0\)  (\(B\)  and \(L\)  are the net baryon number and lepton number respectively),
as required by most extensions
of the SM, but could have rather different NP interpretations [1]}. No measurements for these decays currently exist, but complementary
searches such as \(\tau ^- \rightarrow \Lambda h^-, \overline{\Lambda } h^-\)  (with \(h = \pi ,K\) ) have been performed by
BaBar and Belle, with limits of order \(10^{-7}\)  obtained [2]}.
